| Studies on chemical modification of polypropylene are very active in recent years, in which grafting modification is quite valid. (Maleic anhydride)-graft-polypropylene(PP-g-MAH) was prepared in melting graft. The crystalliza-tion properties and rheology of PP-g-MAH were studied at first and the-n its spinning was studied.At first, the kinds of factors which influence melting graft were discussed. It was showed that maleic anhydride was grafted on polypropylene for sure. The optimal concentration of MAH is 5g/100gPP. The graft degree can be increased if the second monomer of styrene was joined in the reactive system, but be-ing not suitable for our aim. The concentration of initiator should be controlled at 0.6-0.8%. the temperature of four processing zones in twin screw extruder should be controlled at respectively: 165-170℃, 190℃, 190℃, 160-170℃. The screw speed should be between 50-55rpm.This article also studied the crystallization behaviors of PP-g-MAH. the degree of crystallization of PP-g-MAH is lower than that of PP at same isothermal temperature and time by X-Ray testing, furthermore it gets lower with the increasing of graft degree. At isothermal crystal, the spherulite growth rate of PP is mostly quickly at 125℃, but 130℃ for PP-g-MAH, at same time, the mostly quick speed of PP-g-MAH is lower than PP. It is showed that the main growth rate of PP-g-MAH crystal is more quick than PP. The crystallization activation energy is a little larger than that of PP.The rheological behavior of PP-g-MAH is discussed in this article. The melting PP-g-MAH is typical non-newton liquid. The viscosity of PP-g-MAH gets higher with the decrease of temperature, and the elevated extent is equivalent to PP at high shear rate, otherwise it is bigger than PP at low shear rate, the viscometric flow activation energy of PP-g-MAH is higher a little than PP at low shear rate ,butbeing a little lower at high shear rate. The non-newton index of PP-g-MAH is smaller than that of PP, and increases when the temperature get higher.Spinning of PP-g-MAH was studied in the paper. We studied on the stru -cture and performance of PP-g-MAH fibre. Based on the rheology and spin-able ability of PP-g-MAH, the spinning technics was certained. Melt spinning of PP-g-MAH is possible with standard spinning equipment.Experimental results indicated that the breaking tenacity of the graft fiber is smaller than that of polypropylene fibre and decreasing with the increasing of degree of grafting, the opposite result applies to the breaking elongation; breaking tenacity and elongation not only of hollow PP fibre but of hollow PP-g-MAH fibre is lower than that of the common sectional fibre. Orientation degree of PP-g-MAH fibre is bigger than that of PP fibre at same drawn rate. The orientation degree increases with the increasing degree of graft-ing, the orientation degree of hollow fibre is lower than that of common sectional fibre.In addition that, the rudimental quantity of MAH in fibre was studied. It shows that the rudimental quantity of maleic anhydride is 3.7-12.2% of the degree of grafting, which shows that it is the grafted maleic anhydride that changes the properties of PP fibre.The moisture absorption of graft fibre increases evidently by contrast with polypropylene fibre and increases 3-5 times than the PP fibre at the same drawn ratio. The moisture absorption of graft hollow fibre increases by 70-80% with PP hollow fibre.Some innovation can be concluded as follows:1. several methods by which MAH was grafted on polypropylene were compared completely. Melting graft was the right way in which PP-g-MAHwas prepared for spinning fibre.2. The crystallization properties and rheology of PP-g-MAH prepared by melting graft were studied completely at first time. PP-g-MAH was spun fibre at first time. The moisture absorption of the fibres were studied primarily.
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